Richmond Police say they are medically evaluating a teen in connection to Thursday's assault and homicide involving two young children.

Police now have a warrant for the suspect in the crime.

Family members and friends say the suspect sexually assaulted a 12-year-old girl and killed her 8-year-old brother in the 200 block of Brandon Road. Initially, the suspect was described as a white male with scraggly facial hair.

Now police say the suspect, a teenage black male, threatened the victim into giving false information.

According to an aunt of the two children, the siblings were playing in their backyard, near train tracks, in the 200 block of Brandon Road. The suspect beat the boy to death. His sister is recovering in the hospital.

The family is in extreme disbelief and despair. A loved one, too distraught to show her face on camera, says those closest to the two children are barely coping.

"Nobody expects something like this to happen to the babies in their family," said the relative.

The sister was rushed to the hospital.

"She's just traumatized," said the woman.

"All I can say is that it's just...tears, family members falling out...children not understanding what's happening at this point," said Markeita Boyd, a friend of the family. Boyd stayed close to the victim's mother throughout the evening.

The family is left to come to terms with the unthinkable.

"We just took [the mother] on a ride around the block. She doesn't understand why her and why her kids," added the relative.

The boy's stepfather said he had one message for the public. That message- never leave your children unattended, even in your own backyard.

"[We are] still trying to put this thing together," said Richmond Police Major Scott Booth. "As I get more information, I will definitely get that out to you, especially when it comes to a suspect."